Internet Engineering Task Force (IETF) O. Dornon
Request for Comments: 8220 J. Kotalwar
Category: Informational V. Hemige
ISSN: 2070-1721 Nokia
R. Qiu
mistnet.io
Z. Zhang
Juniper Networks, Inc.
September 2017
Protocol Independent Multicast (PIM)
over Virtual Private LAN Service (VPLS)
Abstract
This document describes the procedures and recommendations for
Virtual Private LAN Service (VPLS) Provider Edges (PEs) to facilitate
replication of multicast traffic to only certain ports (behind which
there are interested Protocol Independent Multicast (PIM) routers
and/or Internet Group Management Protocol (IGMP) hosts) via PIM
snooping and proxying.
With PIM snooping, PEs passively listen to certain PIM control
messages to build control and forwarding states while transparently
flooding those messages. With PIM proxying, PEs do not flood PIM
Join/Prune messages but only generate their own and send them out of
certain ports, based on the control states built from downstream
Join/Prune messages. PIM proxying is required when PIM Join
suppression is enabled on the Customer Edge (CE) devices and is
useful for reducing PIM control traffic in a VPLS domain.
This document also describes PIM relay, which can be viewed as
lightweight proxying, where all downstream Join/Prune messages are
simply forwarded out of certain ports and are not flooded, thereby
avoiding the triggering of PIM Join suppression on CE devices.
Dornon, et al. Informational [Page 1]RFC 8220 PIM Snooping September 2017Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
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approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8220.
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Table of Contents
1. Introduction ....................................................4
1.1. Multicast Snooping in VPLS .................................5
1.2. Assumptions ................................................6
1.3. Definitions ................................................6
1.4. Requirements Language ......................................7
2. PIM Snooping for VPLS ...........................................7
2.1. PIM Protocol Background ....................................7
2.2. General Rules for PIM Snooping in VPLS .....................8
2.2.1. Preserving Assert Triggers ..........................8
2.3. Some Considerations for PIM Snooping .......................9
2.3.1. Scaling .............................................9
2.3.2. IPv4 and IPv6 ......................................10
2.3.3. PIM-SM (*,*,RP) ....................................10
Dornon, et al. Informational [Page 2]RFC 8220 PIM Snooping September 2017
2.4. PIM Snooping vs. PIM Proxying .............................10
2.4.1. Differences between PIM Snooping, Relay,
and Proxying .......................................10
2.4.2. PIM Control Message Latency ........................11
2.4.3. When to Snoop and When to Proxy ....................12
2.5. Discovering PIM Routers ...................................13